1. Field of the Invention
The present invention relates to an ultraviolet light emitting diode package, and more particularly, to an ultraviolet light emitting diode package including a light emitting diode chip for emitting light with a peak wavelength of 350 nm or less.
2. Discussion of the Background
Recently, a light emitting diode (LED) has been used for various applications including light sources for illumination, sterilization, purification and medical treatment. In order to use an LED as a light source for illumination, the LED is required to have luminous power of a few tens lumens or more. The luminous power of the LED is generally in proportion to input power. Accordingly, high luminous power can be obtained by increasing power input to the LED. However, the increase of the input power causes junction temperature of the LED to increase. The increase of the junction temperature of the LED results in decrease of photometric efficiency indicating a degree where input energy is converted into visible light. Therefore, the LED is required to have a structure for preventing the increase of the junction temperature of the LED due to the increase of the input power.
An LED package with such a structure is disclosed in U.S. Pat. No. 6,274,924B1 (entitled “Surface mounting LED package”). According the document, since an LED die is thermally coupled on a heat sink, the LED die can be maintained at a low junction temperature. Accordingly, relatively high input power can be supplied to the LED die, so that high luminous power can be obtained.
However, a light emitting diode package (hereinafter, referred to as an LED package) having such a structure, i.e., an LED package capable of obtaining high luminous power with large input power, has not been suggested in various structures and shapes. This is because the LED package has a technical difficulty in commercialization in spite of its simple structure. In particular, since it is not easy to analyze the heat generated from the LED package itself and there are few specialists therefor, the development of the LED package is restrictedly performed. However, since such an LED package is expected to be applied to not only illumination but also large-sized TVs, displays and the like, and its application fields will be extended in the future, various LED packages having superior heat dissipation characteristic are required to have structures and shapes different from a conventional LED package.
In particular, an ultraviolet (UV) LED, which is to produce UV light with a short wavelength, has superior performance in terms of antibiosis, anti-dust, purification, sterilization and the like, so that its application area has been extended to home electronic appliances, such as air cleaners, water purifiers, refrigerators, air conditioners and dish washers, medical appliances, and the like.
A UV LED for producing UV light with a light emitting peak wavelength of 380 to 420 nm, which is a relatively long wavelength, is mainly used as a conventional UV LED. In such a peak wavelength range, the performance of UV light is degraded in terms of antibiosis, anti-dust, purification, sterilization and the like. Nevertheless, as UV light has a shorter wavelength, the performance and lifespan of an LED package including a UV LED are more degraded. For this reason, there is a limit to development of a UV LED with a short peak wavelength.